Science Abuse Posted July 7, 2002 Report Share Posted July 7, 2002 picked this up from a post on another thunderbird board, from a very reputable source: "If you blow off air, it MUST go to the front of the turbo. If not, it's air that was measured by the MAF, and the fuel was put in accordingly, but the air isn't there so it's rich. Most turbos use a wastegate, not a blow off." So, the blowoff air goes into the intake ahead of the turbo, i.e. between it and the air filter, right? Wont that spool the turbo, add boost to the intake, and negate having blown the air off? I'm not sure, but I think the T04E has an internal waste gate...anyone know for sure? I'll find out, one way or another Quote Link to comment Share on other sites More sharing options...
20G TSi Posted July 7, 2002 Report Share Posted July 7, 2002 Originally posted by BlackBird: picked this up from a post on another thunderbird board, from a very reputable source: "If you blow off air, it MUST go to the front of the turbo. If not, it's air that was measured by the MAF, and the fuel was put in accordingly, but the air isn't there so it's rich. Most turbos use a wastegate, not a blow off." So, the blowoff air goes into the intake ahead of the turbo, i.e. between it and the air filter, right? Wont that spool the turbo, add boost to the intake, and negate having blown the air off? I'm not sure, but I think the T04E has an internal waste gate...anyone know for sure? I'll find out, one way or another The BOV does not have to be routed back into the intake of the turbo. It does help with spool (example: build boost, lift. The air from the BOV still has the compressor wheel moving a bit, so less spool time). Its not necessary, even with a MAF IF again, IF it seals properly with vacuum. The o2 will see a rich condition as soon as you lift and correct itself. NOW if you are using a stand alone speed density EEC that uses Manifold Absolute Pressure and throttle position to regluate air/fuel then it doesnt matter if you vent it back to the MAF or into the atmosphere. I'm sure someone will correct me if I'm wrong. Quote Link to comment Share on other sites More sharing options...
slow4now Posted July 7, 2002 Report Share Posted July 7, 2002 A wastegate is just the method of controlling the amount of boost produced by a turbo.It goes on the exhaust side of the turbo, and recieves a pressure signal from the compressor side of the turbo or from the intake. It allows exhaust gas to bypass the turbine, this limiting the amount of boost created. There are two types of wastegates, internal and external. A BOV goes anywhere between the compressor side of the turbo and the throttle body. It is used to prevent compressor surge. Compressor surge is caused when the positive pressure created by the turbo bounces off of a closed throttle plate (when shifting at WOT for example) and causes the compressor to slow down and spin the other way. This is very hard on the bearings of the turbo, and also increases lag because the turbo looses inertia and must be spooled again. MAF's sensors convert the amount of air entering the intake into a voltage signal for the ECU. The ECU then knows what the engine load is and adds fuel accordingly. If any air is lossed that was measured by the MAF a rich-run condition occurs, becuase there isn't enough air to go with the fuel that was dialed in by the ECU. So a BOV that vents to the atmosphere can cause problems with cars that have MAF's, like when going off throttle from WOT. It should be noted that there are different MAF designs (vane and Karmen come to mind, I'm sure there are others). Some BOV's work better venting to the atmosphere when installed on a MAF metered car than others. The HKS SS works well, the Greddy Type-S and Apex-i Twin-Chamber don't. If I were you, I would use an external wastegate as internal wastegates can have problems with boost creep when running high boost. Just make sure that the external wastegate mounts at the collector (for lack of a better term, it may be the proper one I dunno!)of the mannifold and not in any one exhaust mannifold runner. I hope I am making some sort of sense! Later. Quote Link to comment Share on other sites More sharing options...
Guest relvinnian Posted July 7, 2002 Report Share Posted July 7, 2002 Originally posted by BlackBird: I'm not sure, but I think the T04E has an internal waste gate...anyone know for sure? I'll find out, one way or another They can be ordered both internal or not. I recommend external, and I wouldn't fuck around with your wastegate choice either. Nice post babyjesus. Quote Link to comment Share on other sites More sharing options...
Guest FixHondas Posted July 11, 2002 Report Share Posted July 11, 2002 If you put your BOV before your MAF you will be fine (if your MAF is after your turbo). Loss of air after the MAF causes a rich condition. If your MAF is on your turbo inlet you are SOL. [ 11 July 2002, 07:48 PM: Message edited by: FixHondas ] Quote Link to comment Share on other sites More sharing options...
Guest slammed T25 civic Posted July 17, 2002 Report Share Posted July 17, 2002 Some cars, like dsm's for example have the turbo vent back into the turbo inlet pipe with the air directed at the turbo. This helps keep the turbo spooled up between shifts since the air that is blown off has some force to it and is being blown onto the compressor side. On a DSM if you vent into the atmosphere the car will run like shit because you are venting off air that has already been counted and fuel has been added for the exact amount of air. When that air is vented, you will be running rich. I've heard there is one way to make it so you can vent to the atmosphere by replacing you MAF with a different type of sensor. Something like whats on the honda. I think its called a MAP sensor or something similar. If you goto the link I provided at the bottom, it will explain in much greater detail, and have people that you could contact for more information. http://www.dsmtalk.com/forums/showthread.php?s=01175ae24cd99e2205ddd0a397684a53&threadid=30252 Nick Quote Link to comment Share on other sites More sharing options...
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